vbapg — Calculates the gains for a sound location between multiple channels.
k1[, k2...] vbapg kazim [,kelev] [, kspread] [, ilayout]
karray[] vbapg kazim [,kelev] [, kspread] [, ilayout]
ilayout -- index of the speaker layout in the range 0-99, corresponding to a call to vbaplsinit. The default value is 0.
kazim -- azimuth angle of the virtual source
kelev (optional) -- elevation angle of the virtual source
kspread (optional) -- spreading of the virtual source (range 0 - 100). If value is zero, conventional amplitude panning is used. When kspread is increased, the number of loudspeakers used in panning increases. If value is 100, the sound is applied to all loudspeakers.
vbapg calculates the gains that an input signal would have between multiple speakers according to the controls kazim and kelev, and the configured loudspeaker placement ilayout. If idim = 2, kelev is set to zero. The distribution is performed using Vector Base Amplitude Panning (VBAP - See reference). VBAP distributes the signal using loudspeaker data configured with vbaplsinit. The signal is applied to, at most, two loudspeakers in 2-D loudspeaker configurations, and three loudspeakers in 3-D loudspeaker configurations. If the virtual source is panned outside the region spanned by loudspeakers, the nearest loudspeakers are used in panning.
Warning | |
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Please note that all vbap panning opcodes require the vbap system to be initialized using vbaplsinit. |
Ville Pulkki: “Virtual Sound Source Positioning Using Vector Base Amplitude Panning” Journal of the Audio Engineering Society, 1997 June, Vol. 45/6, p. 456.
Here is an example of the vbapg opcode. It uses the file vbapg.csd.
Example 974. Example of the vbapg opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<CsoundSynthesizer> <CsOptions> ; Select audio/midi flags here according to platform -odac ;;;realtime audio out ;-iadc ;;;uncomment -iadc if realtime audio input is needed too ; For Non-realtime ouput leave only the line below: ; -o vbap4.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 4 ;quad 0dbfs = 1 vbaplsinit 2.01, 4, 0, 90, 180, 270 instr 1 asig diskin2 "beats.wav", 1, 0, 1 ;loop beats.wav kaz line 0, p3, p4 ;come from right rear speaker & k1,k2,k3,k4 vbapg 180, 100, kaz, 1 ;change spread of soundsource printks "spread of source = %d\n", 1, kaz ;print spread value outq asig*k1,asig*k2,asig*k3,asig*k4 endin </CsInstruments> <CsScore> i 1 0 12 100 e </CsScore> </CsoundSynthesizer>
Its output should include lines like these:
spread of source = 0 spread of source = 8 spread of source = 17 spread of source = 25 spread of source = 33 spread of source = 42 spread of source = 50 spread of source = 58 spread of source = 67 spread of source = 75 spread of source = 83 spread of source = 92 spread of source = 100